Motor-car heater



Jan. 28, i930.

C. S. PELTON MOTOR CAR HEATER Filed March 2, 1926 2 Sheets-Sheet C25/'e7' 51 Felton Zzzv'en for' Jan. 28, 1930. 3.4 s. PELTON MOTOR CAR HEATER Filed Maron 2, 1926 2 Sheets-Sheet S. .Pelozz Clyde Patented Jan.y 28, A193() UNITED STATES PATENT OFFICE CLYDE S. PELTON, OF CLEVELAND HEIGHTS, OHIO, ASSIGNOR TO THE EATON AXLE @s SPRING COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO MOTOR-CAR HEATER Application inea Marcha, 1926. serial No. 91,718.

This invention relates to motor car heaters and has for its objects the provision of a device of this character which shall heat the car interior uickly without noise or danger of leakage of exhaust gases therein; the provision of a heater which shall operate by the introduction of clean, fresh air taken from the exterior of the car and free from dust and moisture; the provision of an improved type of combined muler and heater wherein both the heating of the air and the cooling and mufling of the exhaust gases shall be facilitated; the provision of a heater of the character described wherein the parts can be readily assembled and tested Jfor leakage or other defects; while further objects and advantages of the invention will become apparent as the description proceeds.

In the drawings accompanying and forming a part of this application I have shown certain physical forms in which my inventive idea can be embodied.v Figs. l and 2 are respectively a side elevation and a top plan view of a standard form of motor car illustrating in full lines the parts more particularly concerned in my invention, the remaining portions being shown in dotted lines; Fig. 3 is a detail sectional view corresponding to the line 3 3 of Fig. 2 looking in the direction of the arrows; Fig. 4 is a side elevation of the air inlet device shown in Figs. 2 and 3; Fig. 5 is a longitudinal ysectional view through the combined muiiier and air heater; Fig. 6 is a sectional view corresponding to the line 6-6 of Fig. 5; Fig. 7 is a longitudinal sectional view through the air heating por- `tion of the muliler shown in Fig. 5; Fig. 8 is a section of a modified form of tube closure; and Fig. 9 is a longitudinal sectional View through one type of inlet and control tting for the heated air; and Fig. 10 is a cross section on theline 10-10 of Fig. 9.

For the successful operation of a motor car heater the irst two requirements are that the back pressure on the motor shall not be increased and that no danger shall exist of the leakage of poisonous exhaust'gases into the body of the car. The next requirement is `that the car shall be heated rapidly, since many cold weather drives are not more than lifteen to twenty minutes in duration and excepting in commercial vehicles a heater loses much of its value that does not exhibit its eect almost immediately upon starting the motor. Other requirements are that it shall be susceptible of being turned off completely when heat is not wanted, and that it shall operate noiselessly. A further requirement is that it shall not introduce dust, dirt, -smoke or odors into the car, and a final requirement is that it be trouble proof and made at reasonable expense.

The requirement of rapid heating is in some ways the most difficult to meet owing to the continuous improvements in motors whereby the motors have become so eiicient as to discharge the gas at comparatively low temperatures. This requires that the largest possible percentage of the hot gases become available for heating purposes, and this requirement, plus the requirement of avoiding odors, is better served by the heating of a large amount of air through a comparatively small rise of temperature than heating a small volume of air to a comparatively high temperature and afterwards mingling the same with the air in the car. According to my invention all these requirements are met by the employment of a peculiar and improved construction of muffler provided with air heating devices through which is rapidly passed a large volume or" fresh air surrounded on all sides by the exhaust gases, and spread out in a thin rapidly moving sheet so as rapidly to abstract as much as possible of the heat carried by the exhaust gases. As a result of the complete surrounding of the air stream by the exhaust gases no opportunity of heat loss is permitted; the passage of a large amount of air through the multler and into the car body produces a rapid change of the temperature of the air in the car; the constant introduction of the cool air into the muiler results in a more rapid heat exchange; and the elect of this rapid air flow is to cool the muiler to such an extent that desiccation of dust particles is prevented, which avoids the production of unpleasant odors. At the same time the rapid cooling of the exhaust gases exhibits a highly beneicial muffler action.

My improved air heater and muier is shown in detail in Figs. and 6 and comprises an outer shell 1, a central pipe 2, and an intermediate annular air heating chamber 3 interposed between the same and defined by the cylindrical tubes 4 and. 5 respectively. The shell 1 is preferably made of sheet metal such as soft steel, rolled to cylin. drical shape and seam-welded longitudinally as shown at 6 in Fig. 6, its opposite ends being provided with pressed metal heads 7 and 8 suitably welded thereto. It can also be formed intermediate its lengt-h if desired with one or more transverse welds 9. The head 7 is located at the forward end of the muflier and is formed with a central aperture receiving the socket 10 adapted for the reception of the exhaust pipe 11 leading from the internal combustion motor 12. The tube 2 leads from this socket a considerable distance axially into the shell 1. The head 8 is located at the rear end of the muffler and is formed at its center with an aperture for th'e reception ofthe neck 15 of t-he heating chamber, this neck being securely and tightly welded or otherwise secured to the head. The head 8 is also provided at some point between said neck and the shell 1 with an outlet fitting 16 adapted for the reception of a pipe 17 by which the exhaust gases are carried to and discharged at the rear end of the Cal'.

The tubes 4 and 5 are so chosen as when concentrically arranged to be spaced from each other and also from the outer shell and central pipe, respectively. At the forward end of the muiiier these tubes are tightly joined together as by the pressed metal annulus 20 welded or otherwise lhermetically united therewith, and at the rearward end the neck 15 is suitably connected to the outer tube 4, as by an annulus 21. lThe rear end of the inner tube 5 is also provided with a suitable closure, hermetically welded or otherwise sealed thereto. In its preferred form this closure consists of a thimble drawn out of sheet metal having a skirt 22 which enters the tube end and an infolded apex 23 which faces the tube 2 and tends to facilitate the reversal in flow of the exhaust gases. This second feature is not imperative and can be omitted or otherwise handled. It will be seen that this heating element forms a separate, simple, complete unit which `can be completed and pressure-tested, before inclusion in the muler.

Between the tubes 4 and 5 near the closure last described I have shown a bracing element 24 consisting of a scalloped ring of sheet metal. Inside the tube 5 I have shown two similar bracing elements 25, adapted to receive the central pipe 2. Outside the tube 4 I have shown a plurality of apertured-sheet metal rings 26 which have the double function of bracing the tube against theA shell and of distributing the flow of exhaust gases.

Near its forward end the tube 4 is formed at one side with a lateral cylindrical neck 28. which ts tightly in an outturned neck 29 70 carried by the outer shell. These parts are also sealed or welded in a leak tight manner and an external pipe 30 can also be united thereto as shown in Fig. 5. f

4The air to be heated is passed through this 75 heating chamber in either direction depending upon the convenience of the user, and this is generally determined by the position of the muilier as compared with the space to be heated. When it is desired to heat the rear 80@ compartment of a motor car as illustrated in Fig. 1 it is generally more convenient to connect the neck 15 to the discharge fitting, but when the car has only one compartment, or when the forward compartment is the one S5 to be heated or when the muffler is located unusually far aft it may be more convenient, to connect the pipe 30 to the discharge fitting Y and the neck 15 to the inlet fitting. In the latter case it is desirable that the cupped 90,'

portion 23 of the closure thimble be covered with a guide plate 31 as shown in Fig. 5. Another convenient construction is shown in Fig. 8 wherein the closure thimble is not reversed but4 constitutes a peaked cap having 95 its lip 22a surrounding the tube 5 and its peak 23a turned away therefrom in which case I may employ a suitably formed spreader 31a inside the cap. A

The outlet o? hot-air discharge fitting may 100 take any one of many forms although the one I prefer is shown in Figs. 9 and y10. An oblong sheet metal plate 35 is formed at the center and near one end with depending hollow necks 36 and 37, and to the latter is se- 105 cured the flexible tube 39 which leads froml the heating unit, either' the neck 15 or the pipe 30 as may be convenient. Secured on top of the plate -is a housing 40 having a flat oblong apertured top 41 and slanting apertured 110 sides 42. These sides terminate in flat flanges 43 which engage the plate and ,between the flanges and the sides a narrow recess 44 is formed which receives the marginal lip 45 of a slidable valve member 46. yThe length of `1l5 this member is such as to enable it toccover both necks when moved to one end of the slide and to uncover one of them when moved to i the opposite end. The body of this valve is,

displaced above the plane of its lips 45 to 120v produce a chamber through which commumcation is established between the necks in the first named position. The top 41 is longitudinally slotted for an operating stud 47 carried by the valve. I have shown a friction spring 125 48 for helping hold the valve in the place to which itis moved and to prevent rattling.

The air inlet fitting may also assume an one of many forms and locations, althou l); my preferred construction is as follows:

each side of the car body a vertical frame member 50 is usually provided and the sides 51 ofthe body which are more or less vertical at their upper parts are here bent laterally as at 52 and then downwardly as at 53 producing an apron which defines a downwardly opening hollow gap. This gap is often occupied by the vehicle springs at the rear, but along the middle of the car adjacent to the running board 54 is generally empty and is peculiarly sheltered from sand, dust, mud, or

water although a strong current of air exists therein when the car is moving.

This location also has the advantage of proximity to the muffler and here I preferably locate the air inlet fitting 55, which consists of a funnel shaped metal hood, shaped to fit the space and opening forwardly. At its rear it has a hole 56 in one side for attachment of the pipe 57 leading to the air heateriy I have shown a bailie plate 58 designed to obstruct the entrance of dust and a slant to the bottom of the hood at 59 to shed water and sand.

This combination of muffler and air heater Ahas peculiar advantages from both aspects.

Its operation as a muffler is noticeably improved by the cooling effect of the air. Immediately upon entering the mufiier the hot gases come in 4contact with cooled surfaces which are kept cooled by the rapid passage of large volumes of air on the opposite side. Also this cooling of the gases by heat interchange is followed by an expansion of the same into the larger outside chamber of the niufller, thus further cooling them adiabatically so that the reduction in volume produced by the cooling taken in conjunction with the increase in space provided by the construction described reduces the pressures to such a point that noise is effectively muffled; and this result being produced almost wholly by cooling no tendency exists to create back pressure.

Its operation as a heater is characterized by the rapid passage of a very large volume of the cool air over surfaces heatedby the exhaust gases before they have had an opportunity to become cooled adiabatically. A larger amount of heat is abstracted by a large volume of air moving at high speed and heated a little than by a small volume of air moving more slowly and heated a great deal. Hence the air passages are made as few, as smooth, as simple, and as unbroken as possible. The result is the production of a torrent of warm air into the compartment to be heated, not hot enough to incinerate the dust particles nor to injure rugs and robes, but producing a substantial heating immediately upon starting. Owing to the fact that the hot air chamber is entirely surrounded by the exhaust gases there is little opportunity for heat loss. In` deed, owing to the cooling of the exhaust gas by contact with the outer walls of the mufiler, combined with the heating of the air prior to expansion of the exhaust gases it sometimes occurs that the temperature of the air in the tube 39 is higher than that of the exhaust in the pipe 17.

It will be understood that many changes can be made in all the parts, elements, and combinations herein described and I do not limit myself in anywise except as specifically excluded by my claims.A

Having thus described my invention what I claim is:

1. In a combined muiler and air heater for motor cars, a pair of concentric cylindrical tubes of unequal size located one inside the other and having their walls connected together at one end to define an .annular chamber, the opposite end of the inner tube being closed, a discharge pipe for hot exhaust gases projecting into the open end of said inner tube and defining therewith an annular passage, air circulation connections secured to` opposite ends of the outer tube, and a housing surrounding the said tubes and discharge pipe and having an outlet for the exhaust gases, whereby such gases pass across the surfaces of both the inner and outer tubes.

2. In a device of the character described, two concentric metal tubes having their walls connected together at one end and defining an annular chamber, the opposite end of the inner tube being closed, the opposite end of the outer tube extending beyond the inner tube, inlet and outlet necks connected to opposite ends of said outer tube, a discharge pipe for hot exhaust gases projecting into the` open end of said inner tube and forming therewith an annular passageway, and a housing spaced from and surrounding the said tubes and discharge pipe and having an outlet for the exhaust gases, whereby such gases pass across the surfaces of both the inner and outer tubes.

3. In a device of the character described, the combination with the exhaust pipe of an internal combustion engine, of an annular element separate from and substantially independent of said pipe into the interior of which said pipe dprojects, said element comprising inner an outer tubes, the inner tube being open on the end into which projects said pipe, the outer tube being entirely closed at lone end and partially closed at the other end, the outer tube being also larger and longer than the inner tube and the walls of said tubes being joined together adjacent the open end of the inner tube to define an annular chamber, a housing around said annular element communicating freely with the interior of said element, said housing having a discharge opening, and means for creating circulation of cool air through said cham- 4. In a combined mufller and air heater, a heating element comprising two concentric metal tubes of unequal size arranged one Within the other, said tubes having their walls connected together adjacent one end to form a closed end defmin an annular chamber, l'the inner of said tues being open at one I5 "end and closed at the other end, in combination with av discharge llilipe -for hot exhaust gases projecting into e open end of said v inner tube 'and defining therewith an annular passage, and aphousing surrounding'the ex- 10- terior of said element and communicating with said passage, saidi housing having an exhaust outlet at the end opposite to the end of said annular chamber where the exhaust gases enter, and said element being provided 15- at opposite' ends with air inlet and'outlet connections which traverse said housing.,

5. In a combined muier vand ai'r heater a unitary, structurally independent, air' heating element comprising inner and outer 20 metal tubes of unequal length and diameter having their walls joined together at one end and having closures to separate the respective tubes, a pipe for hot exhaust gases proj ecting intothe open-end of the smaller tube and spacedtherefrom to define an annular passage, anf'outer'shell around said larger tube and s aced therefrom to define a surrounding amber, a head connected to said shell and pipeand spaced from said tubes, 3o and air circulation connections communicating with opposite ends of said heating element, said surrounding chamber having an outlet.A e In testimony whereof I hereunto aix my signature.

- n f Y t CLYDE S. PELTON. 

